“With the new package, the engine runs in its sweet spot at any given speed, never straying from its sweet spot at any point from zero through top speed.” –Ed Saxman, product manager–powertrain, for Volvo Trucks North America (VTNA) commenting on the OEMs new integrated “XE13” integrated powertrain package introduced in late 2011
“Integration” is a hot topic of late in trucking circles, as OEMs and fleets alike seek ways to drive down fuel consumption while simultaneously maintaining or even improving overall vehicle performance. Indeed, I spent several days last week with some of the top executives from Daimler Trucks North America (DTNA) discussing this “integration” trend and what they’re doing along in that area.

Now, integration is nothing new in the truck OEM world – indeed, Landon Sproull, chief engineer for Peterbilt Motors Co., told me in a recent interview that “integration” is at the core of what truck makers do for a living, both in the past in the present; taking a range of disparate parts, from axles to transmissions and engines, and packaging it all together on a chassis frame.
The difference today, though, is that OEMs and fleets alike are keeping the pressure on to wring every smidgen of efficiency out of trucks of all shapes and sizes today in search of savings no matter how small – whether it’s by burning less fuel, lengthening service intervals, or reducing downtime for maintenance. And that’s where this new emphasis on integration comes into play.

Take Volvo Trucks North America’s (VTNA) new XE13 (with the “XE” standing for “exceptional efficiency”) powertrain package unveiled in September last year.
It combines Volvo’s proprietary I-Shift automated manual transmission (AMT) and D-13 engine with modified software in a VN Class 8 tractor model to allow the vehicle to “cruise” down the highway under load at 65 mph with the engine only cranking at 1150 rpm – about 200 rpm less than the average truck sold today, noted Ed Saxman, VTNA’s product manager–powertrain.
“Customers gain about a 1.5% fuel efficiency improvement for every 100 rpm of ‘downspeeding’ like this, so fleets specing the XE13 package can expect up to a 3% fuel economy improvement when compared to another overdrive transmission in a similar operation,” he explained. more…